This invention relates to a spool for use in a blasting system and, more particularly, is concerned with a spool which includes an elongate flexible signal transmitting conductor which in use is connected to a detonator.
A flexible signal transmitting conductor such as a conductive wire, a fibre optic cable or a shock tube is often provided, for use in a blasting system, in a coiled and compact form. One end of the conductor is connected to a detonator while an opposing end is connected to an appropriately designed connector. The connector is one of a plurality of similar connectors which are electrically or otherwise coupled to a harness or distribution system. In use each detonator, suspended from the respective signal transmitting conductor, is lowered into a respective borehole to a suitable depth. Thereafter an explosive composition is placed into the borehole with a detonator, a length of the signal transmitting conductor then being embedded in the explosive composition.
A large blasting site can include a significant number of boreholes. The installation of the detonators inside the boreholes and the deployment of the associated signal transmitting conductors can thus constitute a laborious and time consuming undertaking. When a signal transmitting conductor is played out care should be exercised to ensure that the coils do not become ensnared one in the other. The subsequent interconnection of the detonators to a harness, on surface, is also time consuming. The uncoiling of a length of the conductor which is not to be located inside a borehole should be avoided for the uncoiled conductor, on surface, is an impediment to free movement and, moreover, the conductor can be physically damaged due to a variety of factors.
Boreholes at a blast site or at different blast sites may be of different depths and the length of conductor required for each borehole thus can vary from borehole to borehole. Logistical issues are also associated with the storage and transport of a substantial number of coiled signal transmitting conductors.
An object of the present invention is to address, at least to some extent, the aforementioned factors.